In Chapter 2 I describe the disparity in speeds between the hardware processor of a computer and file storage technology: the former operates in microseconds, while the latter operates in milliseconds. There is potentially a major waste of processor hardware when a processor makes a request for some file storage data and has to wait for a long time to receive it. One option is for the processor to idle: effectively doing nothing. The other option is for the operating system of the computer, for example Windows, to ask the processor to carry out some other task; this is a process known as multi-tasking. In Chapter 4 you will meet a concept known as grid computing. This is a technology that connects a number of processors together in such a way that they take advantage of this slack resource. This article describes another use for slack resources on a home PC: running computational programs that help into biomedical research. Your home computer will use slack processor resource to carry out computations while you are, for example, retrieving word-processed files.